This Application claims priority from EP 05100617.9 filed Jan. 31, 2005, the entire disclosure of which is incorporated herein by reference thereto.
1. Field of the Invention
The invention relates to a device for measuring a mass flow rate of a flow of particulate material which moves in a predetermined direction, said predetermined direction of flow.
The invention relates more specifically to a device for measuring a mass flow rate of a component introduced in an extruder, such as the main component, but also for measuring the mass flow rate of additional components such as colour masterbatches, if used in combination with a dosing system.
Designated by particulate material is particularly, but not exclusively, pellets, reground material, coarse powder, plastic masterbatch.
The invention is very useful for measuring the particulate material consumption rate of a machine such an extruder.
Measuring the mass flow rate of each component introduced in an extruder is particularly important when the components are used to extrude a plurality of superposed layers and when the thickness of each layer is difficult or impossible to measure on the extrusion line.
2. Description of the Background Art
Different devices are known for measuring a mass flow rate of a particulate material such as described in U.S. Pat. No. 6,732,597 and EP-A-0213524. These devices are generally based on “loss-in-weight” measurements of a hopper, and good accuracy is only possible when weight difference in the measuring hopper is sufficiently large compared to the total hopper weight.